Apparatus and system for measuring volume of blood loss

ABSTRACT

A system for measuring the blood loss comprises a measuring device that determines a hemoglobin concentration of fluid within a container utilizing a light source and a light detector. The container receives blood and other fluids from a patient during a medical procedure. Light from the light source is passed through the blood and other fluids in the container and is detected by the light detector. Based upon a magnitude of light detected, a hemoglobin concentration of the fluid in the container can be determined. A volume-measuring device determines the volume of blood and fluid in the container. Knowing the hemoglobin concentration and volume of fluid in the container, the volume of patient blood loss in the container can be determined. The blood loss measuring device in combination with infusion systems maintains a real-blood volume status so that proper infusion of blood, crystalloid and/or colloid solutions occurs.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. Provisional PatentApplication No. 62/320,991 filed on Apr. 11, 2016, the entirety of whichis incorporated by this reference.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to devices, systems, and methods for measuringblood loss of a subject, and more particularly, to devices, systems, andmethods for measuring the blood loss of a subject during a surgicalprocedure.

Field of the Invention

During surgical procedures, it is often necessary to assess the amountof patient blood loss in order to determine whether a transfusion ofblood or other intravenous fluid is needed to maintain properblood/fluid levels of the patient. Unnecessary blood transfusions,coupled with over/under administration of IV fluids, however, arefrequently associated with poor patient outcomes. During such medicalprocedures, blood, irrigation fluids and other bodily fluids arecollected in a suction canister. As such fluids collect in the suctioncanister, conventional methods of estimating blood loss requiresoperating personnel to estimate the amount of blood contained in thesuction canister by visual inspection. Because the suction canister mostoften includes unknown quantities of other fluids in addition to blood,such visual estimates can be quite inaccurate.

While the majority of the blood lost by the patient in surgery iscollected in the suction canister, the primary method for assessing thevolume of blood in a suction canister during surgery is to use acombination of visual assessment of the volume reading on the canisterand knowledge of how much irrigation fluid has been used during fluidsuctioning. The volume of irrigation fluid is then subtracted from thevolume in the canister to determine how much fluid in the canister isblood and is based on an inaccurate assumption that any fluid that isnot irrigation fluid must be blood. Visual assessment of blood in thesuction canister is also not accurate and requires a visual assessmentby a member of the surgical team, yet remains the primary method ofassessment today.

Other attempts in the art to determine the amount of blood in thesuction canister have included the use of a digital scale to weigh thesuction canister and surgical sponges in order to estimate blood loss.More recently, a photographic method has been employed based on digitalphotography in which a digital image taken by a smartphone or similarhandheld device is used to measure hemoglobin in surgical sponges.Attempts have also been made to use this method with a suction canisteras well.

During many surgical procedures blood loss can be significant and mustbe carefully monitored to ensure that the patient maintains proper andsufficient fluid levels during such procedures. Blood, bodily tissue,bone fragments and other fluids and materials are removed from thesurgical cite by suction. In addition, saline solution is used toirrigate the surgical site during an operation and thus will accompanythe removal of blood, bodily tissue, bone fragments and other fluids andmaterials removed by suction. These materials and fluids are collectedin the suction canister during the operation. When the volume of bloodloss reaches a threshold level, a transfusion is typically required.Excessive blood loss without such transfusions can lead to seriouscomplications or death. It is therefore important to monitor theblood-saline (and other possible constituents) mixture to determine amore precise volume of blood that has been lost by the patient during amedical procedure. If the volume of blood lost can be continuously andquickly monitored, blood loss rates can also be determined.

A typical canister tree in an operating room can hold six to eightsuction canisters. A surgery with medium-level blood loss will requireone to three 2 L suction canisters. As one canister becomes full, fluidsbeing removed by suction are switched to the next available canister.The suction canisters are made to be disposable and currently costapproximately $1.30 each. Thus, it would be desirable for anyblood-measuring device that may be part of or included with the canisterto also be relatively inexpensive and disposable so that the entire unitcan be discarded when the medical procedure is finished. Since operatingrooms and surgical procedures can be tedious, active, crowded by thepresence of the attending surgical team, and require rapid decisionmaking, it is also desirable to have a blood monitoring system that iseasy to use and provides real time and easily observable blood lossreadouts.

Thus, there is a need in the art for a device, system and method foraccurately and quickly measuring the blood loss of a subject during asurgical procedure. The present invention satisfies this need bycombining a fiber-optic based light emitter or other similar lightsource and sensor to determine hemoglobin concentration in a fluidmixture within a suction canister along with either amicro-electromechanical (MEMS) sensor to measure fluid pressure withinthe suction canister or an optical method contained within the sensorthat measures fluid levels from which the volume of the fluid mixturewithin the suction canister can be determined. By knowing the hemoglobinconcentration and total fluid volume within the suction canister, thevolume of blood loss of a patient can be accurately determined in realtime.

SUMMARY OF THE INVENTION

The present invention comprises a blood measurement device fordetermining the amount of blood of a subject within a fluid sample. Theblood measurement device includes a light source, at least one lightsensor, such as a photodetector, and a processor which analyzes thesignals arising from the light source and the at least one light sensor.The light source is configured to selectively generate light at two ormore different wavelength bands. The light source and the at least onelight sensor are configured for positioning in an operative position. Inthe operative position, the at least one light sensor is configured toreceive at least a portion of the light generated by the light source.Upon positioning of the light source and the at least one sensor in theoperative position, the at least one light sensor is configured toproduce a signal indicative of the absorbance of the fluid sample at aselected number of wavelength bands. Absorbance is a combination ofabsorption, transmission, scattering, and fluorescence. The processor isoperatively coupled to the at least one light sensor and is configuredto receive the signals from the at least one light sensor. Based uponthe signal from a selected number wavelength bands, the processor can beconfigured to determine the concentration of hemoglobin within the fluidsample. Optionally, the processor can be further configured to determinethe volume of blood within the fluid sample

The blood measurement system may also include a volume sensor to providetotal fluid volume within the container, such as a suction canister, inwhich the hemoglobin concentration is being determined according to thepresent invention. By knowing the hemoglobin concentration and thevolume of fluid in the container, the volume of patient blood within thecontainer can be determined.

Also disclosed are blood measurement systems including the bloodmeasurement device and a container, such as a suction canister.Optionally, portions of the blood measurement device can be selectivelyinsertable within a fluid sample positioned within the suction canister.

Methods of determining the blood loss of a subject are also disclosed.The methods can include operatively positioning the blood measurementdevice relative to a fluid sample and using the blood measurement device(alone or in combination with conventional methods) to determine theconcentration of hemoglobin within the fluid sample. Optionally, themethods can include administering one or more reagents to the interiorspace of the suction canister. Optionally, the reagents can beconfigured to convert hemoglobin within the fluid sample into eithermethemoglobin or sulphemoglobin. The methods can optionally include thestep of delivering an anti-coagulant to the fluid sample.

These and other advantages and features of the invention are more fullydescribed in the detailed description of the invention with reference tothe drawings. The advantages of the invention will be realized andattained by means of the elements and combinations particularly pointedout in the appended claims. It is to be understood that both theforegoing general description and the following detailed description areexemplary and explanatory only and are not restrictive of the invention,as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

When considered in connection with the following illustrative figures, amore complete understanding of the present invention may be derived byreferring to the detailed description. In the figures, like referencenumbers refer to like elements or acts throughout the figures.

FIG. 1 is a front side view of a blood volume measuring apparatus inaccordance with the principles of the present invention.

FIG. 2 is a partial front side perspective view of a hemoglobinconcentration and pressure sensing probe of the blood volume measuringapparatus shown in FIG. 1.

FIG. 3A is a partial front side view of the hemoglobin concentration andpressure sensing probe shown in FIG. 1 illustrating the path of a lightray.

FIG. 3B is a partial front side view of the hemoglobin concentration andpressure sensing probe shown in FIG. 1 illustrating another path of alight ray.

FIG. 4 is a graph illustrating signal in form of ratios versusconcentration in percentages in accordance with the principles of thepresent invention.

FIG. 5 is a schematic block diagram of various components of a bloodvolume measuring apparatus in accordance with the principles of thepresent invention.

FIG. 6 is a front side view of the blood volume measuring apparatus ofFIG. 1 when connected to a patient in accordance with the principles ofthe present invention.

FIG. 7 is a schematic block diagram of various components of a bloodvolume measuring apparatus in accordance with the principles of thepresent invention.

FIG. 8 is a partial front side view of another embodiment of ahemoglobin concentration and pressure sensing probe of a blood volumemeasuring apparatus in accordance with the principles of the presentinvention.

FIG. 9 is a partial front side view of yet another embodiment of ahemoglobin concentration and pressure sensing probe of a blood volumemeasuring apparatus in accordance with the principles of the presentinvention.

FIG. 10 is a graph showing a received signal versus a blood liquid levelof a blood volume measuring apparatus in accordance with the principlesof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention can be understood more readily by reference to thefollowing detailed description, examples, drawings, and claims, andtheir previous and following description. However, before the presentdevices, systems, and/or methods are disclosed and described, it is tobe understood that this invention is not limited to the specificdevices, systems, and/or methods disclosed unless otherwise specified,as such can, of course, vary. It is also to be understood that theterminology used herein is for the purpose of describing particularaspects only and is not intended to be limiting.

The following description of the invention is provided as an enablingteaching of the invention in its best, currently known embodiment. Tothis end, those skilled in the relevant art will recognize andappreciate that many changes can be made to the various aspects of theinvention described herein, while still obtaining the beneficial resultsof the present invention. It will also be apparent that some of thedesired benefits of the present invention can be obtained by selectingsome of the features of the present invention without utilizing otherfeatures. Accordingly, those who work in the art will recognize thatmany modifications and adaptations to the present invention are possibleand can even be desirable in certain circumstances and are a part of thepresent invention. Thus, the following description is provided asillustrative of the principles of the present invention and not inlimitation thereof.

Unless specifically noted, it is intended that the words and phrases inthe specification and the claims be given their plain, ordinary, andaccustomed meaning to those of ordinary skill in the applicable arts. Itis noted that the inventor can be his own lexicographer. The inventorsexpressly elect, as their own lexicographers, to use only the plain andordinary meaning of terms in the specification and claims unless theyclearly state otherwise and then further, expressly set forth the“special” definition of that term and explain how it differs from theplain and ordinary meaning. Absent such clear statements of intent toapply a “special” definition, it is the inventor's intent and desirethat the simple, plain and ordinary meaning to the terms be applied tothe interpretation of the specification and claims.

The inventors are also aware of the normal precepts of English grammar.Thus, if a noun, term, or phrase is intended to be furthercharacterized, specified, or narrowed in some way, then such noun, term,or phrase will expressly include additional adjectives, descriptiveterms, or other modifiers in accordance with the normal precepts ofEnglish grammar. Absent the use of such adjectives, descriptive terms,or modifiers, it is the intent that such nouns, terms, or phrases begiven their plain, and ordinary English meaning to those skilled in theapplicable arts as set forth above.

Further, the inventors are fully informed of the standards andapplication of the special provisions of 35 U.S.C. § 112, ¶ 6. Thus, theuse of the words “function,” “means” or “step” in the DetailedDescription of the Invention or claims is not intended to somehowindicate a desire to invoke the special provisions of 35 U.S.C. § 112, ¶6, to define the invention. To the contrary, if the provisions of 35U.S.C. § 112, ¶ 6 are sought to be invoked to define the inventions, theclaims will specifically and expressly state the exact phrases “meansfor” or “step for” and the specific function, without also reciting insuch phrases any structure, material or act in support of the function.Thus, even when the claims recite a “means for . . . ” or “step for . .. ” if the claims also recite any structure, material or acts in supportof that means or step, or that perform the recited function, then it isthe clear intention of the inventor not to invoke the provisions of 35U.S.C. § 112, ¶ 6. Moreover, even if the provisions of 35 U.S.C. § 112,¶ 6 are invoked to define the claimed inventions, it is intended thatthe inventions not be limited only to the specific structure, materialor acts that are described in the illustrated embodiments, but inaddition, include any and all structures, materials or acts that performthe claimed function as described in alternative embodiments or forms ofthe invention, or that are well known present or later-developed,equivalent structures, material or acts for performing the claimedfunction.

In the following description, and for the purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the various aspects of the invention. It will beunderstood, however, by those skilled in the relevant arts, that thepresent invention may be practiced without these specific details. Inother instances, known structures and devices are shown or discussedmore generally in order to avoid obscuring the invention. In many cases,a description of the operation is sufficient to enable one to implementthe various forms of the invention, particularly when the operation isto be implemented in software. It should be noted that there are manydifferent and alternative configurations, devices and technologies towhich the disclosed inventions may be applied. Thus, the full scope ofthe inventions is not limited to the examples that are described below.

Various aspects of the present invention may be described in terms offunctional block components and various processing steps. Suchfunctional blocks may be realized by any number of hardware or softwarecomponents configured to perform the specified functions and achieve thevarious results.

As used throughout, the singular forms “a,” “an” and “the” includeplural referents unless the context clearly dictates otherwise. Thus,for example, reference to “a photodetector” can include two or more suchphotodetectors unless the context indicates otherwise.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

As used herein, the terms “optional” or “optionally” mean that thesubsequently described event or circumstance may or may not occur, andthat the description includes instances where said event or circumstanceoccurs and instances where it does not.

The word “or” as used herein means any one member of a particular listand also includes any combination of members of that list.

As used herein, a “subject” is an individual and includes, but is notlimited to, a mammal (e.g., a human, horse, pig, rabbit, dog, sheep,goat, non-human primate, cow, cat, guinea pig, or rodent), a fish, abird, a reptile or an amphibian. The term does not denote a particularage or sex. Thus, adult and newborn subjects, as well as fetuses,whether male or female, are intended to be included. A “patient” is asubject afflicted with a disease or disorder. The term “patient”includes human and veterinary subjects. As used herein, the term“subject” can be used interchangeably with the term “patient.”

Described herein with reference to the figures are devices, systems, andmethods for measuring blood loss of a subject. It is contemplated thatthe disclosed devices, systems, and methods can provide a more accuratemeasurement of blood loss during a surgical procedure than conventionaldevices, systems, and methods. As further disclosed herein, thedisclosed systems and methods can be used to iteratively estimate thehemodilution of a subject based on the kinetics of intravenous fluidadministration and blood loss. It is further contemplated that thedisclosed blood measurement devices and systems can directly measure theamount of blood in a suction canister or other fluid collectioncontainer based upon the estimated hemodilution of the subject. Thus, itis contemplated that the disclosed system can iteratively estimate thehemoglobin status of the subject intraoperatively by taking into accounta baseline estimation of the patient's intravascular blood volume (EBV)and preoperative hemoglobin status, the volume of intravenous fluidsadministered to the subject, as well as the volume and hemoglobinconcentration of the fluid within the suction canister. The updatedestimated hemoglobin status of the subject can then be used toaccurately calculate the new volume of blood loss in the suctioncanister.

As further described herein, it is contemplated that the discloseddevices, systems, and methods can optionally employ algorithms todetermine the concentration of hemoglobin within a fluid sample and/orthe blood loss experienced by a subject during a medical procedure.However, it is contemplated that the disclosed devices, systems andmethods can be used in conjunction with any conventional method ofpredicting a subject's hemoglobin concentration and/or the volume of afluid sample containing the blood of a subject. Thus, although exemplaryalgorithms for determining hemoglobin concentration and blood loss areprovided herein, it is understood that the devices, systems, and methodsdisclosed herein are not restricted to use with particular algorithms.For example, when the hemoglobin concentration within a fluid sample andthe volume of the fluid sample are known (i.e., provided as an input tothe processor of the device or determined by the device), it iscontemplated that the disclosed devices, systems, and methods can beused in conjunction with conventional methods for determining one ormore of the following: the subject's preoperative hemoglobinconcentration; an updated hemoglobin concentration of the subject,determined from a subject's blood sample; an updated hemoglobinconcentration of the subject, based upon an estimate provided by apractitioner (e.g., an anesthesiologist); or an updated hemoglobinconcentration of the subject, based upon a continuous, non-invasivemethod as is known in the art. It is contemplated that, when an updatedhemoglobin concentration of the subject is determined, the preoperativehemoglobin concentration of the subject can be averaged with the updatedhemoglobin concentration to permit determination of the amount of bloodlost by the subject. It is further contemplated that the averagedhemoglobin concentration can be provided to a processor as disclosedherein in the form of one or more user inputs.

FIG. 1. Illustrates a first embodiment of a device, system and method toreliably and accurately determine an amount of blood loss by a patientduring surgery or other medical procedure. The blood loss measuringsystem, generally indicated at 10, comprises a single sensor probeassembly 12 that is configured to be inserted, insertable or built intoa suction container 14 or other container into which blood from apatient and other fluids are collected during a medical procedure, suchas surgery. The probe sensor 12 includes light sensor probes 16 and 18for determining hemoglobin concentration in mixture with other fluids,such as saline, within the suction container 14 and a pressure sensorprobe 20, both of which are in fluid communication with an interior 22of the suction container 14. The sensor probe assembly 12 is optionallyconfigured to be disposable along with disposable type suctioncontainers. The sensor probe 12 according to the present invention isconfigured to come into contact with blood and other fluids in thesuction container 14 and is configured to be an expendable, low-costdevice so that the sensor probe 12 may be discarded after a single useor single medical procedure.

The system 10 also includes a pressure-measuring device, which includesthe pressure sensor probe 20 is configured to provide total fluid volumewithin the container 14. Thus, both the pressure sensor probe and lightsensor probes for measuring hemoglobin concentration within thecontainer 14 are incorporated into the single probe 12 that is easilyinsertable or built into a suction canister or container 14. It shouldbe noted that the terms “container” and “canister” are usedinterchangeably throughout and are intended to mean the vessel withinwhich blood and other fluids are collected during a medical procedure.The hemoglobin concentration sensor system 24 utilizes the principle ofoptical absorption to determine a percentage of hemoglobin in the fluidcontained within the container 14. Each wavelength of light from a whitelight source 26 passes through blood and other fluids within thecontainer 14 and is measured by a spectrum analyzer 28, such as amicrospectrometer or any suitable instrument for measuring wavelengthdistributions. The total blood/fluid mixture volume within the suctioncontainer 14 is measured by sensing pressure through the pressure sensorprobe 20. The pressure sensor probe 20 is thus used to determine liquidheight within the suction container 14 utilizing the tube 30 that isincorporated into the same probe as the optical blood sensor. The tube30 is coupled to and thus in fluid communication with amicro-electromechanical pressure sensor 31 to measure fluid pressurewithin the suction canister 14 from which a volume of the fluid mixturewithin the suction canister 14 may be determined. If the reducedpressure in the canister becomes significant then a differential (or asecond) pressure sensor can be used to measure the pressure above thefluid to provide appropriate compensation.

The blood-loss monitoring system 10 of the present invention comprises abroad-spectrum light source 24 that connects to an optical fiber 32 thatextends from the light source 24 into the canister 14 and forms thedistal end of the hemoglobin concentration sensor probe 16. Light thatpasses from the end 32′ of the fiber 32 through blood in the canisterloses strength due to both absorption and scattering. A second plasticoptical fiber 34 having an end 34′ proximate to the end 32′ of the firstoptical fiber 32 collects the remaining light that has not been absorbedor scattered and sends it to the spectrometer 28, such as amini-spectrometer. The output 36 of spectrometer 28 allows a display ofthe received intensity for all wavelengths in the visible and nearinfrared. Such a display is termed a transmission spectrum. Analysis ofthe spectrum, the collection of intensities of all wavelengths,indicates the percentage of hemoglobin mixed with other fluids asdiscussed herein.

The optical fibers 32 and 34 and pressure sensor tube 30 can be madesufficiently long that the instrumentation 24, 28 and 31 for generatingreadings from light received from the optical fibers 32 and 34 andpressure sensor tube 30 will not physically interfere withoperating-room activities. In other words, the length of such componentsoptical fibers 32 and 34 and pressure sensor tube 30 can allow forremote placement of the light source 26, spectrometer 28 and pressuresensor 31.

The light source 26, spectrometer 28 and pressure sensor 31 areelectronically coupled to a processor 37. The processor 37 is configuredto receive readings from the spectrometer 28 and pressure sensor 31, todetermine hemoglobin concentration and fluid volume from the sensorreadings and to determine blood volume in the container 14 from thedetermined hemoglobin concentration and fluid volume. The processor 37is also coupled to a display 38 for displaying in real time, the volumeof blood loss of the patient.

Once the processor 37 determines the concentration of hemoglobin in thecontainer 14, the processor 37 uses this information to then determine aresulting blood loss measurement. In addition to displaying thisinformation, the processor can be connected to and coordinate with aninfusion system (known in the art) to thereby control and monitor bloodinfusion during a surgical procedure. Such infusion systems are employedin surgeries where blood infusion is being deployed to limit excess orinsufficient blood infusion to ameliorate a patient's condition during aprocedure.

Likewise, the resulting blood loss measurement may be used by theprocessor to calculate and control infusion volumes of crystalloid orcolloid solutions to replace blood loss during surgical procedures, tothereby limit excess nor insufficient crystalloid/colloid infusions,which can be harmful to the patient.

The probe assembly 12 is inserted into a top port 40 of the operatingroom suction canister 14 and abuts against an inside bottom surface 42of the suction canister. The distal end 44 of the probe assembly 12includes a pair of legs 46 and 48 to space the distal ends of theoptical fibers 32 and 34 and distal end of the pressure tube 30 from thebottom surface 42 of the canister 14. The distal ends of the opticalfibers 32 and 24 are sufficiently spaced from the bottom surface of thecontainer 14 so that tissue or other heavy particles that may sink tothe bottom of the container will not interfere with the transmission oflight between the ends of the optical fibers. Likewise, the legs 46 and48 space the distal end of the pressure sensor tube 30 from the bottomsurface 42 of the container 14 so that such particles do not interferewith pressure readings for volume measurements.

Referring now to FIG. 2, a close up view of the distal end of the probeassembly 12 is shown. The probe assembly 12 comprises two plasticoptical fibers 32 and 34 used to take a hemoglobin concentrationmeasurement between the distal ends 32′ and 34′ of the optical fibers 32and 34, respectively. The pressure tube 30, which may be comprised of aplastic tube, is used to determine the height H of fluid F in thecontainer from which the volume of fluid in the container can bedirectly determined. By knowing the volume of the liquid in the canisterand the hemoglobin concentration, an instantaneous amount of blood inthe canister can be determined.

As previously discussed, the distal end 44 of the probe 12 is configuredto be inserted in the canister and rest upon the bottom surface 42 ofthe canister 14. The pressure tube 30 connects back to the pressuresensor 31 (see FIG. 1). The distal ends 32′ and 34′ of the two opticalfibers 32 and 34 are cut and polished at oppositely angled 45-degreeangles. These angled surfaces cause light (indicated by arrows) to bedirected from one fiber 32 through a gap between the distal ends 32′ and34′ of the optical fibers 32 and 34 and into the second fiber 34,whereby the reflected light is transported up the fiber 34 and to thespectrum analyzer 28 (see FIG. 1). Fluid F that resides in the gapformed between the fibers 32 and 34 absorbs and/or scatters at least aportion of the light leaving the fiber 32 before it reaches the fiber34. By knowing the intensity of light that is received by the fiber 34when the container 14 is empty, a light intensity difference can bedetected when fluid is present in the container 14 and the ends 32′ and34′ are submerged in the fluid.

The probe assembly 12 includes a housing 50 comprised of a pair offacing housing members 52 and 54. The housing members 52 and 54 are heldtogether with fasteners 56. The housing members 52 and 54 define aplurality of vertical channels 56, 57 and 58 therein between for housingthe optical fibers 32 and 34 and pressure tube 30, respectively. Thehousing member 52 also includes the legs 46 and 48 to contact the bottom42 of the container 14 when the probe assembly 12 is fully inserted intothe container 14. The legs provide a space between the fiber optic ends32′ and 34′ and pressure tube end 30′ and the bottom 42 of the container14 so that a sufficient volume of blood within the container and belowthe optical fiber ends 32′ and 34′ can be measured and the end of thepressure tube 30 can receive a volume of fluid such that as the level Lof fluid F within the tube 30 causes an increase in air pressure withinthe tube 30 that can be measured with the pressure sensor 31 (seeFIG. 1) in order to determine an instantaneous volume of fluid F withinthe container 14.

As shown in FIGS. 3A and 3B, the 45° angled fiber pairs 32 and 34 areshown to illustrate ray-paths from one fiber to the next includingreflections. The arrows depict a single transmitted light ray from onefiber 32 to the other fiber 34. It is noted, however, that other rays oflight will be entering and reflecting at other angles as well.Reflections within the fiber are nearly 100% efficient if within thenumerical aperture, NA. FIG. 3A illustrates the light ray in a situationwhere there is no fluid (other than air) surrounding the ends of theoptical fibers 32 and 34. In that situation, there is some light lossthat does not pass to the other optical fiber. In FIG. 3B, however, whenfluid is present between the ends of the optical fibers 32 and 34, thereis more transmission of light across the fluid/plastic boundary ofoptical fiber 34 due to index matching of the light.

The numerical aperture, NA, is determined by the following equation:NA=√{square root over (n ₁ ² +n ₂ ²)}where n₁ and n₂ are the respective indices of refraction. In FIG. 3A,the ray of light illustrated by a dashed line indicates reflection of afraction of the ray entering the receiving fiber 34. With no liquid inthe container, this reflection is at a maximum. When fluid is added tothe container, as shown in FIG. 3B, by better index matching, the amountof light lost between fibers 32 and 34 due to such reflection is less.For simplicity of explanation and illustration, it should be noted thatrefraction, which causes bending of light across the media boundaries atthe angled ends of the fibers 32 and 34, has been ignored.

For very dilute concentrations of blood, it may be expected that thecommon Beer-Lambert law will hold for each ray where the transmittedlight, I, by the receiver fiber is dependent on the incident lightlevel, I₀; an attenuation coefficient α; and path length, l.I=I ₀ e ^(−αl)

The received signal in this case will be the summation of I for each raythat crosses between the fibers. Depending on the angle, the individualpath lengths will be different. As the hemoglobin concentration rises,then the attenuation coefficient will have added to it an additionalcomplicating factor, scattering, μ_(s). Thus, α_(total)=α+μ_(s). Becausethis is not a simple scalar quantity it is difficult to model. Some rayswill travel much farther in the blood due to several scattering events.In addition, the scattering effect is more or less pronounced atdifferent wavelengths. Through testing by the applicants, α and μ_(s)work in concert to achieve blood level sensitivity according theprinciples of the present invention.

The mini-spectrometer 28 shown in FIG. 1 provides data files comprisingintensities versus wavelength. The data is analyzed in order todetermine hemoglobin concentration in the container 14. Some wavelengthsof light are not absorbed significantly by blood while others areabsorbed much more readily. Additionally, some wavelengths of lightreflect and scatter differently from other wavelengths. In addition, thescattering characteristics versus wavelength are a function of dilutionby other constituents that will be present in the container 14. Forexample, saline solution is often used as an irrigating medium duringsurgical procedures. The saline solution is removed along with blood bysuction and collected in the suction canister 14. Also some wavelengthsmay produce fluorescence in yet other wavelengths. By illuminating thefluid within the suction canister 14 by either a broad spectrum lightsource or even a pair (or more) of specific wavelengths of light and theresults are observed and compared with the same or other wavelengths, aratio formed between such wavelengths can in some combinations be afunction of hemoglobin concentration in the fluid contained in thesuction canister. The inventors note that there are a number of possiblewavelength pairs (triads, or more) from which to choose and that somewavelength pairs (triads, or more) produce better results than others.Combinations of these pairs (triads, or more) can be included for evengreater accuracy and/or range.

The processor 37 receives data from the spectrum analyzer 28 anddetermines resultant accuracy expected for all possible wavelengthpairs. The analysis performed by the processor determines the bestwavelength pair from which to determine hemoglobin concentration withthe least uncertainty. The spectrum analyzer groups the intensity of acontinuum of wavelengths into discrete bins for analysis. From thesemeasurement pairs of wavelengths are selected for analysis. In practicea pair should be separated by a minimum distance that insures no overlapof the intensity measurements. Here a ratio for each unique possiblewavelength pair is formed. The wavelength pair and results are highlydependent on sensor design, especially the gap between the fibers. Eachratio is plotted versus hemoglobin concentration. A curve is fitted tothe data. The greater the slope of this fit through the data, thegreater the sensitivity. It is not only necessary to show a highsensitivity but also satisfy the other factors listed in the paragraphsherein. The greater the accuracy for a given pair of wavelengths, thebetter that wavelength pair is for measuring hemoglobin concentration.In order to discover the most viable pairs a three-dimensional contourplot is formed with axis 1 and axis 2 being each wavelength in a pairand axis three providing the “overall goodness of fit” as defined by theminimum uncertainty (greatest accuracy) on the independent variable(hemoglobin concentration). Peaks on the contour plot show effectivewavelength pairs for accurate measurement. That is, at such pairs theratio is strongly hemoglobin concentration dependent with minimaluncertainty and therefore greatest accuracy. These results can also bedisplayed with a spreadsheet that is easy to use which will produce theresults of interest. The optimal wavelength pair(s) is unique to theparticular probe design and construction, since different sensor designsmay have distinctive absorption paths. It should also be noted that, forsources that are light emitting diodes (LEDs), since an LED light sourceis not a pure line but a Gaussian distribution, it is straightforward touse a Gaussian-weighted average around the peak wavelength incalculating the result. This value can be set over any range. A usefulvalue generally is about 50 nm. Subsequently, after LEDs or other lightsources are selected, the actual wavelength distributions may be usedfor modeling and testing. Once a wavelength pair(s) is selected, theabove analysis is reduced to the calibration obtained for that pair. Thefinal product would only need the intensities of the desired wavelengthsand the fixed calibration obtained.

Since the excitation light intensity can vary over time, measuringabsolute intensities does not necessarily produce consistent results.However, a good assumption is that only the overall light intensityvaries and the relative individual wavelength intensities stayconsistent relative each other. Therefore, by generating a ratio of theintensities the overall amplitude cancels out and the result is a uniquenumber that is independent of the overall intensity.

For a given wavelength pair the ratio is computed and linked to thehemoglobin content of the sample. When enough samples are gathered thatcover a desired hemoglobin concentration range, the statisticallyacceptable results can be plotted with the ratio on the ordinate and thehemoglobin content on the abscissa. A curve is generated that best fitsthese points and analyzed with respect to the best conditions of fit asset forth herein. This process is repeated for all unique wavelengthpairs possible and the wavelength pairs that produce the best resultsare utilized.

To test the system for measuring blood loss according to the principlesof the present invention, human blood from a blood bank contained in asingle pouch was used in sample sets to maintain the relative hemoglobinconcentration of the 100% sample. Each sample was precisely measured anddiluted with saline to form a specific hemoglobin concentration frombetween 5% to 100%. Each sample was also measured with a HEMOCUEhemoglobin analyzer to confirm each blood sample's hemoglobinconcentration and to provide an absolute reference. The system formeasuring blood loss according to the principles of the presentinvention was able to determine the relative dilution of each sample.

As such, the system for measuring blood loss according to the principlesof the present invention can accurately provide the concentration ofhemoglobin in a suction canister containing blood, various other fluids(such as saline) and other constituents (such as tissue and/or bonefragments) in the suction canister during a medical procedure (such assurgery). In order to more accurately provide to medical personnel amore precisely calculated blood loss volume of the patient resultingfrom the detected hemoglobin concentration of the fluid in the canister,the initial hemoglobin concentration of the patient must be known. Oncethe hemoglobin concentration of the fluid in the canister is measured,the volume of fluid in the canister is known (by determining volume byusing the pressure sensor as described herein, by using light sensors asdescribed herein, by video detection, by visual inspection or othermeans), and the initial or real time hemoglobin concentration of thepatient's blood before being diluted by saline and/or other fluids andconstituents in the canister are known, the system for measuring bloodloss according to the principles of the present invention can determinetotal blood loss in real time. The patient's hemoglobin concentrationcan be provided to the system for purposes of calculating blood loss invarious ways. First, by making an assumption that the patient's bloodhemoglobin concentration remains constant throughout the surgery, apre-op hemoglobin concentration measurement can be taken before surgery.This is a reasonable assumption for surgeries not lasting many hourssince hemoglobin concentration tends to remain relatively constant forshort surgeries. Second, an estimate of how much of the patient'shemoglobin concentration is changing during the surgery, for examplebased on IV administration of saline or other fluids to the patientduring surgery by which the system decreases or increases the hemoglobinconcentration from an initial hemoglobin concentration according tocurves that have been generated based on historical data of hemoglobinconcentrations of patients compared to volume of saline and/or otherfluids administered during surgery. Third, the patient's actualhemoglobin concentration could be measured throughout the surgery,either invasively or noninvasively. The measured hemoglobinconcentration is then input into the system in real time as part of thereal time blood loss volume calculation provided by the system of thepresent invention. Thus, by knowing the blood source concentration, theabsolute hemoglobin concentration can accordingly be accuratelyobtained.

Once a wavelength pair(s) is selected, the above analysis is reduced tothe calibration obtained for that pair. The blood loss measuring systemof the present invention would then only need the intensities of thedesired wavelengths and the fixed calibration obtained to determinehemoglobin concentration within the suction canister.

One method of calculating an estimated blood loss (EBL) is set forthbelow. The method uses total Hgb mass (g) lost in canister as a fractionof original Hgb mass in patient. First, the total Hgb mass (g) in thecanister is calculated. After adjustment for units,Volumec (cc)/100×Hgbc (g)=total Hgb mass (g) in canister

Next, the preop Hgb mass (g) of patient is calculated.

TBV=total blood volume

After adjustment for units,TBV (cc)/100×preop pt Hgb (g)=total preop Hgb mass (g) of patient

Next, the percent of Hgb mass (g) lost in canister is calculated.% Hgb mass lost (g)=% blood lost from preop TBV=EBL (cc)

The most accurate way to assess TBV is to use the Nadler's equation.

Patient Total Blood Volume (mL) Male (0.006012 × H³/(14.6 × W) + 604Female (0.005835 × H³)/(15 × W) + 183

-   -   where H=height in inches and W=weight in pounds.

Another way to estimate Total Blood Volumes is based on Gilcher's Ruleof Five.

Blood Volume (mL/kg of Body Weight) Patient Obese Thin Normal MuscularMale 60 65 70 75 Female 55 60 65 70 Infant/Child — — 80/70 —

The reason for the difference is secondary to the difference invascularity between adipose tissue and muscle tissue. For very obesepatients the total blood volume can be estimated by using the lean bodyweight plus 20%.

For pediatric patients, the Total Blood Volume can be estimated asfollows:

Approximate Blood Volume Age group (mL/kg) Premature infant at birth 90-105 Term newborn infant 80-90 Children (<3 months) 70-75 AdolescentsMale 70 Female 65

The blood loss measuring system 10 of the present invention may beembodied in a number of related but different manifestations. Forexample, using data acquired by a broad-spectrum light source and amini-spectrometer, hemoglobin concentration can be determined. Utilizingsuch results to determine one or more optimal wavelength pairs, two (ormore) LED light sources that closely match at least one of the optimalwavelength pairs can be selected. Utilizing a broadband light source andspectrometer provides the greatest accuracy at the greatest expense. TheLEDs that produce light of the optimal wavelength(s) can replace thebroadband light source and eliminate the need for a spectrometer greatlyreducing cost.

In order to determine the best or optimal wavelengths for a given probedesign, the following approach may be taken:

-   -   1) By using a ratio approach according to the present invention,        light source intensity variations are eliminated. It is this        ratio that is used as the input to the resultant algorithm that        produces the percent hemoglobin concentration.

%  Concentration = f(r) = a ⋅ r² + b ⋅ r + c where:$r = \frac{I_{1}\left( {{IntensityOfWavelength}\mspace{11mu}{\# 1}} \right)}{I_{0}\left( {{IntensityOfWavelength}\mspace{11mu}{\# 0}} \right)}$

-   -   2) A necessary constraint is that there be a monotonic        relationship of the particular wavelength ratio pair to the        hemoglobin concentration over the range of interest. (If it is        not monotonic then more than one answer is available for a given        input.)    -   3) A further requirement is that the selected wavelength ratios        be most sensitive throughout the range of the resultant        hemoglobin concentration. That is, the slope of the line of the        ratio versus the concentration is the largest obtainable. This        insures a small uncertainty in the percentage of hemoglobin        calculated.    -   4) In addition, the measured data, to have the highest accuracy,        must have the smallest standard deviation of fit to the        resultant empirical function, whether a polynomial, a spline, a        piecewise fit, or other function, which relates the ratio of the        selected wavelength pairs chosen to determine the hemoglobin        concentration.    -   5) Also of concern is the variation of fit (accuracy) over the        region of interest to account for slight variations in the        manufacturing of the sensor probes. That is, small variations in        wavelengths of interest and probe design should produce the same        result.    -   6) Fitting the measured ratio (y) to the percent hemoglobin        concentration (x) for quadratics and cubics yields very good        fits for certain pairs of wavelengths. It is important to select        the optimum pair(s) as some available pairs do not show any or        much sensitivity to concentration.    -   7) By using more than one pair of wavelengths, multiple        measurements can be made simultaneously and averaged together        for even more accurate results and less sensitivity to probe        design. Some pairs could share wavelengths (e.g., 3 wavelengths        could produce up to 3 pairs to analyze).

When the “best” or “optimal” wavelengths for a given probe design aredetermined, a curve fit equation can be derived for the actual data. Ifindividual light sources are used (e.g. LEDs) then they may be timemultiplexed requiring only a single photodetector. Also their relativeamplitudes can be tracked over time by measuring them before any fluidenters the canister, which would then be used to compensate any longterm drift. After a few minutes the LED's should achieve thermalstabilization and remain constant for extended periods of time.

As shown in FIG. 4, the actual data matches the derived equation. Thegraph in FIG. 4 compares results of a single test using the probeassembly illustrated in FIG. 1 with a cubic fit to the results for apair of wavelengths with a 0.3% sigma (standard deviation) fit onhemoglobin concentration for the above requirements. To determine theratios that satisfy the above criteria, a full spectrum is measured ateach concentration and all combinations of wavelengths in each spectrumare analyzed. Those ratios that best meet the criteria are then used inthe final analysis. FIG. 4 illustrates a plot of signal (in form ofratio) to concentration (%). Parameters of interest are listed at thebottom of the figure and equation of fit is in lower right of figure.

If the above criteria cannot be met in total or are not accurate enoughfor a single pair, then regions of concentration can be identified thatdo fit the above criteria and different wavelength ratios can then beused for each region. That is, each ratio pair would be valid forrestricted regions of concentration, but when used in combination wouldthen define the entire region of interest.

Other items of interest (urine, Heparin, etc.) might also be measured inparallel by using additional ratios.

As shown in FIG. 5, in a further aspect, the blood measurement device100 can comprise a power source 102 positioned in operativecommunication with one or more light sensors 104, such as aphotodetector, a light source 106 and a processor 110. The power source102 can be positioned in operative communication with the light source106, light sensor 104 and processor 110 through conventional wiring 72.The power source 102 can be any conventional power source as is known inthe art. For example, the power source 102 may comprise a battery. Inother exemplary aspects, it is contemplated that the power source cancomprise a DC power source. In still other exemplary aspects, it iscontemplated that the power source can comprise an AC power source. Theprocessor 110, includes a processor chip such as a microprocessor, andis operably coupled to the light source 106, light sensor 104 andpressure sensor 108. The light sensor 104 and pressure sensor 108 sendsignals to the processor, which signals may comprise analog or digitalinformation to indicate the amount of light being detected by the lightsensor 104 and pressure detected by the pressure sensor 108. Theinformation is then used by the processor 110 to determine a hemoglobinconcentration in the suction canister thereby indicated the amount ofblood loss of the patient. The quantity of blood loss can then bedisplayed on a display 112 that is also operably coupled to theprocessor 110. In addition, the processor 110 may be operably coupled toone or more fluid control systems 114 such as an IV drip system toincrease fluid to the patient depending on the amount of fluid loss ofthe patient or to an blood transfusion system to increase blood flow tothe patient to account for any blood loss detected by the blood lossmeasuring system 100 of the present invention.

In use, and as schematically depicted in FIG. 5, it is contemplated thatthe blood loss measuring system 100 can be configured to create afeedback loop at any given time between the calculated patienthemoglobin concentration and the hemoglobin concentration and volume ofthe sample fluid, thereby resulting in a continuous display of estimatedpatient blood loss. After the blood loss measuring system 100 calculatesthe estimated blood loss and the updated patient hemoglobinconcentration based on the data output from the light sensors asdisclosed herein, the results can be transmitted to a memory and/ordisplay 112 that are in communication with the processor 110.

As shown in FIG. 6, the blood loss measuring system 10 comprises theblood measurement probe 12 and a container 14, such as, for example andwithout limitation, a suction canister 20. Although described herein asa suction canister, it is contemplated that the container can be anyconventional container that is configured to receive a fluid sample F.For example, in exemplary aspects, it is contemplated that the containercan be a cell saver, which is configured to clean a fluid sample topermit delivery of the fluid sample to a patient. It is contemplatedthat the suction canister 14 can be configured for operative coupling toone or more sections of suction tubing 120 as are conventionally usedduring surgical procedures to facilitate transport of bodily fluidsand/or irrigation fluids to the suction canister 14. It is furthercontemplated that the suction canister 14 can have any conventionalshape, including, for example and without limitation, a substantiallycylindrical shape. It is still further contemplated the suction canister14 can have any selected dimensions. In exemplary aspects, it iscontemplated that the suction canister 140 can have a volume rangingfrom about 0.5 liter to about 5 liters. Fluid from the suction tubing120 is collected in the suction canister 14. The patient 130 may also bereceiving IV fluids and/or blood transfusion through other tubing 132from and IV or blood transfusion system 134.

As fluid F is collected in the canister 14, the blood loss measuringsystem of the present invention determines the volume of fluid F in thecanister 14 and the hemoglobin concentration in the fluid F. Thisinformation is received by the processor 37. The processor 37 calculatesthe estimated fluid volume (EFV) in the canister 14 from either thepressure data received from the pressure sensor 31 or from an opticalsignal analysis of measured optical wavelength bands that, independentor those relevant to or required for the hemoglobin concentration, havesignals that change appropriately to different fluid levels. Thisoptical analysis would determine the depth of the fluid in the canisteror other blood container. The wavelength bands used could be measured astransmissions through the fluid or, more likely, light returning fromthe source that is affected by the properties of the interface betweenfluid and air. Simultaneously, or near simultaneously, but in real time,the processor 37 calculates the estimated hemoglobin blood concentration(EBC) from the concentration of hemoglobin detected in the fluid F.Knowing the EFV and EBC in the canister 14, the processor 37 thendetermines the estimated blood volume (EBV) contained within thecanister 14. This information is then displayed in real time on thedisplay 38. The display 38 may also show the EFV in real time so thatmedical personnel can compare the EFV with the actual fluid volume inthe canister 14 that can be visually seen by such personnel by comparingthe volume of fluid F in the canister 14 with volume indication markingson the canister 14. If there is an unexpected discrepancy between theEFV and actual fluid volume, the system 10 allows personnel the optionto adjust the detected volume level in the system so as to obtain moreaccurate results of the EBV. That is, when the EFV is overridden, theprocessor 37 will recalculate the EBV based on the new EFV.

As shown in FIG. 7, a blood loss measuring system 200 of the presentinvention may comprise a processor 202 as is conventionally known in theart. The processor 202 can be provided in the form of a computer, andthe processor 202 can be in operative communication with memory 204 (orother storage device) and/or a display 206 as are known in the art. Itis contemplated that the memory 204 can optionally store software that,when executed, is configured to perform one or more of the steps andcalculations disclosed herein. It is further contemplated that thememory 204 can store historical information related to the hemoglobinconcentration and/or blood loss of particular patients. In exemplaryoptional aspects, the processor 202 can be provided as a microcontrollerthat is secured to or housed within a portion of the device 200. Asfurther disclosed herein, the processor 202 can comprise one or moremodules for determining at least one of the estimated blood loss (EBL)of the subject, the hemoglobin concentration (Hgb) of the fluid sample,and the volume of the fluid sample. In exemplary aspects, the processor202 can be configured to receive one or more inputs from a user or amemory indicative of at least one of a previously measured EBL of thesubject, a previously measured hemoglobin concentration of the fluidsample, a previously measured volume of the fluid sample, a volume ofthe container (e.g., canister) in which the fluid sample is positioned,the rate of IV fluid (or other fluid) administration, the sex of thesubject, the weight of the subject, the age of the subject, and thelike. Optionally, it is contemplated that the processor 202 can bepositioned in operative communication with a user interface that isconfigured to receive the one or more inputs from a user. In exemplaryaspects, the display and/or user interface can be secured to or definedthereon a portion of the device 200.

The processor 202 may also be operably coupled to one or more monitoringdevices 208, 209 and 210. The monitoring devices may include one or moreexternal patient monitoring devices that may be related to the bloodlevels of the patient that may further be used to indicate accuracy ofmeasurement of the blood loss measuring system of the present invention.The monitoring devices may also include pressure monitoring andblood/hemoglobin concentration of the fluid contained within the suctioncanister as herein described. Thus, the system 200 of the presentinvention may be expanded to include other monitoring devices, whethernow known in the art or that may become known in the future.

For example, the system 200 can further comprise a drip counterconfigured for communication with an intravenous (IV) fluid deliveryelement, such as, for example and without limitation, an N bag as isknown in the art. In this aspect, the drip counter can be configured toproduce a volume signal indicative of the volume of IV fluid dispensedfrom the IV fluid delivery element and/or a delivery rate signalindicative of the rate at which IV fluid is dispensed from the IV fluiddelivery element. It is contemplated that the drip counter can bepositioned in operative communication with the processor 202 such thatthe processor is configured to receive the volume signal and/or thedelivery rate signal. Alternatively, the volume and/or rate informationcan be entered manually by a user of the system 200.

In further exemplary aspects, it is contemplated that the bloodmeasurement system can optionally comprise a plurality of bloodmeasurement devices that have a common processor or, alternatively, thathave discrete processors that are in operative communication with eachother. In these aspects, it is further contemplated that the bloodmeasurement system can comprise a plurality of containers (e.g., aplurality of suction canisters 14), with a blood measurement devicebeing configured for selective positioning relative to a respectivecontainer. It is contemplated that such a configuration can permitdetermination of comprehensive blood loss information in circumstanceswhen more than one container is used to collect fluids during a singlemedical procedure.

Referring again to FIG. 6, in other exemplary aspects, it iscontemplated that a lid 122 of the canister 14 can define one or morereceptacles 40 that are configured to receive at least a portion of theprobe 12. The lid 122 is configured to enclose a top opening of thecanister 14. In these aspects, it is contemplated that the lid of thecanister 14 can define at least one opening configured to receive one ormore portions of the blood loss measuring device 10, including, forexample and without limitation, the probe 12 that houses the opticalfibers and pressures sensor tube.

In one aspect, the suction canister 14 can have a central axis that,during use, is generally axially aligned with the vertical axis. In oneaspect, the suction canister 14 can have a wall with an internal surfaceand an external surface. The internal surface of the suction canister 14can define an interior space of the suction canister 14. It iscontemplated that the interior space of the suction canister 14 can beconfigured to receive the fluid sample F. In exemplary aspects, thesuction canister 14 can comprise conventional plastic materials,including, for example and without, transparent plastic materials. Infurther exemplary aspects, it is contemplated that the suction canister14 can be provided with volume measurement lines and other measurementlines and markings as are conventionally known in the art.

Optionally, it is contemplated that the light sensor optical fibers andpressure sensor tube can be selectively operatively coupled to a wall ofthe suction canister 14. However, in some aspects, it is contemplatedthat the light sensor optical fibers and pressure sensor tube canoptionally be positioned within a central portion of the interior spaceof the suction canister 14 (and radially spaced from the wall of thesuction canister 14).

In other exemplary aspects, it is contemplated that one or morecomponents of the blood measuring device 10 can be integrally formedwith the canister 14. For example, in some aspects, the probe 12 can beintegrally formed with the wall of the canister 14. In further exemplaryaspects, it is contemplated that at least a portion of the opticalfibers disclosed herein can be integrally formed (for example, embeddedwithin) the wall, bottom portion, and/or lid of the canister 14.

It is also contemplated that the blood measurement system 10 cancomprise a stirrer positioned within the interior space 25 of thesuction canister 20. In exemplary aspects, the stirrer can be a magneticstirrer as is known in the art. However, it is contemplated that thestirrer can be any conventional stirrer as is known in the art. It isfurther contemplated that the stirrer can be configured for selectiveactivation. In exemplary aspects, it is contemplated that the stirrercan be positioned proximate the bottom surface of the suction canister14.

In use, the disclosed blood loss measuring system of the presentinvention can be used to measure the amount of blood within a fluidsample. In exemplary aspects, the blood loss measuring system can beused to measure the blood loss of a subject during a medical procedure,such as, for example and without limitation, a surgical procedure. Asset forth herein, it is contemplated that the blood loss measuringsystem can be configured to repeatedly measure the hemoglobinconcentration of the fluid sample within a suction canister, as well asthe volume of the sample fluid within the suction canister. Throughoutthe medical procedure, it is contemplated that the blood loss measuringsystem can be configured to export these measurements to the processor202, which can use the measurements, along with the updatedconcentration of the subject's hemoglobin concentration, to calculatethe volume of blood in the suction container. Thus, a method ofmeasuring the amount of blood of a subject within a fluid sample (e.g.,determining the blood loss of the subject) can comprise operativelypositioning the blood measurement device relative to the fluid sampleand using the blood measurement device to determine the concentration ofhemoglobin within the fluid sample. More specifically, the method cancomprise positioning the light source and the at least one light sensorin an operative position relative to the fluid sample. With the lightsource and the light sensor positioned in the operative position, themethod can further comprise selectively activating the light source tosequentially generate light at the first and second wavelengths. Themethod can further comprise receiving the transmitted light using the atleast one light sensor. The method can still further comprise, throughthe processor, receiving the first and second output signals of the atleast one light sensor and determining the hemoglobin concentrationwithin the fluid sample. In further exemplary aspects, the method cancomprise, through the processor, determining the volume of blood withinthe fluid sample. In still further exemplary aspects, the method cancomprise, through the processor, determining the volume of the fluidsample. Alternatively, it is contemplated that the method can comprise,through the processor, receiving an input indicative of the volume ofthe fluid sample. In further exemplary aspects, the method canoptionally comprise, through the processor, receiving an inputindicative of a starting (or other previously measured) hemoglobinconcentration of the subject.

In exemplary aspects, the hemoglobin concentration of the fluid samplewithin the suction container can be measured through one or morehemoglobinometry techniques as are known in the art. Generally, theseknown color or light-intensity matching techniques can be used tomeasure the concentration of methemoglobin or sulphemoglobin, whichprovide an indication of the overall hemoglobin concentration of thefluid sample within the suction canister. Thus, in various aspects, themethod of measuring the amount of blood of a subject within a fluidsample (e.g., determining the blood loss of the subject) can optionallycomprise administering one or more reagents to the fluid sample. Inthese aspects, the one or more reagents can be configured to converthemoglobin within the fluid sample into one of methemoglobin andsulphemoglobin. In exemplary aspects, the fluid sample can optionally bepositioned within a suction canister as disclosed herein, and the one ormore reagents can be added to the suction canister. In some exemplaryaspects, it is contemplated that the one or more reagents (and/or asolution containing such reagents) can be administered to the internalsurface of the suction canister. In other exemplary aspects, it iscontemplated that the one or more reagents can be added to the suctioncanister 14 (or other container) before the fluid sample is receivedwithin the suction canister (or other container). In further exemplaryaspects, it is contemplated that the one or more reagents can be appliedto selected surfaces of the blood measurement device that are configuredfor positioning within the fluid sample. In these aspects, it iscontemplated that the one or more reagents can be configured tocirculate within the fluid sample following contact between the selectedsurfaces of the blood measurement device 10 and the fluid sample. Insome aspects, the reagents (and/or the solution containing the reagents)can be allowed to air-dry. Alternatively, in other aspects, the reagents(and/or a solution containing such reagents) can be provided at apredetermined concentration such that dilution of the reagents and/orsolution by the fluid sample can yield a desired reagent concentration.

An exemplary method for measuring the methemoglobin concentration withinthe fluid sample comprises the use of hemiglobincyanide (HiCN;cyanmethamoglobin) as a reagent. The use of hem iglobincyanide as areagent is described in Zijlstra W G, Van Kampen E. Standardization ofhemoglobinometry. I. The extinction coefficient of hemiglobincyanide.Clin Chim Acta. 1960 September; 5:719-26, which is incorporated hereinby reference in its entirety. Alternatively, in one exemplary aspect,the reagent can comprise sodium azide or sodium lauryl sulphate, whichconvert the hemoglobin to azidmethemiglobin and hem iglobinsulphate,respectively. Exemplary methods of measuring hemoglobin within the bloodusing sodium azide are described in Vanzetti G. An azide-methemoglobinmethod for hemoglobin determination in blood. J Lab Clin Med. 1966January; 67(1): 116-26, which is hereby incorporated herein by referencein its entirety. Exemplary methods of measuring hemoglobin within theblood using sodium lauryl sulphate are described in Oshiro I, TakenakaT, Maeda J. New method for hemoglobin determination by using sodiumlauryl sulfate (SLS). Clin Biochem. 1982 April; 15(2):83-8, and in LewisS M, Garvey B, Manning R, Sharp S A, Wardle J. Lauryl sulphatehaemoglobin: a non-hazardous substitute for HiCN in haemoglobinometry.Clin Lab Haematol. 1991; 13(3):279-90, both of which are herebyincorporated herein by reference in their entirety. Optionally, in someaspects, it is contemplated that one or more lysing agents can be addedto the solvent. Exemplary lysing agents can be selected from the groupconsisting of desoxycholate, quaternary ammonium salts, and quaternaryammonium surfactants, such as, for example and without limitation,anionic, non-ionic, zwitterionic, and cationic surfactants. In oneexemplary aspect, the following compositions can be added per liter ofsolvent: 40 g sodium desoxycholate (to lyse the cells within the fluidsample); 20 g sodium nitrite (to convert the hemoblogin iron fromferrous to ferric state); and 18 g sodium azide (to formazidmethemoglobin).

Optionally, in various exemplary aspects, the method of measuring theamount of blood of a subject within the fluid sample can furthercomprise delivering an anti-coagulant to the fluid sample. In theseaspects, it is contemplated that the method of measuring the amount ofblood of the subject within the fluid sample can comprise delivering adesired amount of anti-coagulant for each liter of fluid sample that iscollected within the suction canister or other container. In exemplaryaspects, the anti-coagulant can be Heparin. In these aspects, it iscontemplated that the method of measuring the amount of blood of thesubject within the fluid sample can comprise delivering a selectednumber of units of Heparin for each liter of fluid sample that iscollected within the suction canister 20 or other container. Forexample, it is contemplated that that the selected number of units ofHeparin can be about 20,000 units of Heparin per liter of fluid sample.However, it is contemplated that any conventional anti-coagulant drugcan be delivered in a selected quantity relative to the volume of thefluid sample. For example, it is contemplated that the anti-coagulantcan be selected from the group consisting of Ethylenediaminetetraaceticacid (EDTA) and Citrate.

Optionally, in some applications, it is contemplated that a plurality ofanti-coagulants can be delivered to the fluid sample. In furtherexemplary aspects, it is contemplated that the anticoagulant orplurality of anti-coagulants can be provided to the fluid sample in anyform, including, for example and without limitation, liquid or solidforms. Typically, it is contemplated that the anti-coagulant(s) can bedelivered using a syringe as is conventional in the art. However, it iscontemplated that any suitable delivery method can be used. In oneexemplary aspect, it is contemplated that a solid form of theanti-coagulant can be fixedly coupled to the internal surface of asuction canister such that the anti-coagulant contacts the fluid sampleas it fills up the suction canister. In another exemplary aspect, it iscontemplated that a solid form of the anti-coagulant can be fixedlycoupled to selected portions of a base element 80 as disclosed hereinsuch that the base element can be selectively inserted within the fluidsample to provide the anti-coagulant to the fluid sample.

In methods in which anti-coagulants are not provided to the fluidsample, it is contemplated that absorbance data obtained when the fluidsample first enters the canister or other container should be used indetermining the hemoglobin concentration, whereas the absorbance dataobtained following coagulation of the blood within the fluid sampleshould be disregarded. Thus, it is contemplated that the processor canbe configured to disregard absorbance data obtained followingcoagulation of blood within the fluid sample. Alternatively, the methodcan comprise inserting the light source and the at least one lightsensor into the fluid sample before coagulation of the blood within thefluid sample has occurred and removing the light source and the at leastone light sensor from the fluid sample and/or ceasing activation of thelight source and at least one light sensor after coagulation of theblood within the fluid sample has occurred.

While some prior art devices utilize the difference in absorption by theblood of two different wavelengths, the present invention is novel andnonobvious because it utilizes multiple wavelengths across a broadspectral range and uses these in a manner that allows for minimizinguncertainty and allowing for variances in sensor construction and othersituations that may be encountered. Utilizing a spectrum analyzer allowsfor variation in light sources to be compensated.

While LEDs may vary in wavelength, as manufacturers specifications show,the spectrum analyzer can account for such variations. It is alsocontemplated that when selecting LEDs of specific wavelengths, aspectrum analyzer could by utilized in advance to determine the actualwavelength of light being emitted by a particular LED and thenaccounting for the actual frequency of light being emitted by the LEDs.

The present invention provides a region of absorption of light that isoptically engineered in a way different than any prior art absorptionbased sensors. By cutting and polishing the end of the fibers at a 45degree angle and orienting them as in shown in FIGS. 1, 2, 3A and 3B,light is captured efficiently and the curvature of the fiber, whichrelates to optical power, results in an efficient light capturingarrangement. In addition, the optical fibers of the present inventionefficiently capture light that may undergo a number of scatteringevents. Thus, there is not a single absorption path length to which toapply Beer's law, but a distribution of path lengths. As such, the fiberoptic configuration of the present invention provides effective bloodabsorption measurements and has been empirically shown to do so.

Thus the present invention provides a sensor, such as a MEMs sensor, formeasuring pressure (or differential pressure) that is integrated into apackage with an optical system for measuring hemoglobin concentration,or an optical measurement that determines fluid level. The results arecombined to determine the amount of blood loss. An optical absorptionapproach involving the entire visible spectrum enables measurements atvarying concentrations in saline solution. This is achieved using aninexpensive probe assembly. The probe assembly may be entirely comprisedof plastic components that are inexpensive to manufacture and can bediscarded after coming into contact with blood in the canister. Thus,the probe assembly can be made to be disposable. The plastic opticalfibers transport interrogation light and emission light to and from theoperating room canister. The single zone probe is constructed from PMMAand plastic optical fibers, thereby being inexpensive and disposable.The mathematical solution of the present invention in conjunction with aspectrum analyzer provides a 3-dimensional mathematical method forhemoglobin concentration measurement and determination. In addition, thepresent invention provides a probe design and two (or more) appropriatewavelengths or light emitting diodes (LED) wavelengths that will yieldaccurate hemoglobin concentration results. In one embodiment of theinvention, an infrared LED may be used as the emitter and an identicalinfrared LED with an amplifier may be used as the detector or sensor.Such a system, greatly reduces the cost, reduces complexity andeliminates the need for a spectrometer, resulting in an unobtrusivepiece of instrumentation that can be located in the vicinity of theoperating room canister.

Referring again to FIG. 1, the spectrum analyzer 28 and pressure sensor31, in combination with the sensor probe, determine the actual bloodloss in situ during surgery. The major components of the presentinvention include:

It is also contemplated that two (or more) different color LED's couldbe used in lieu of a broad band light source, and identical LED's withelectronic amplifier as detectors. For example, such a system maycomprise:

1. 2 (or more) visible LEDs

2. 2 (or more) IR LEDs

3. Plastic Optical Fibers

4. Plastic Optical Fiber Beam Splitter

5. Plastic probe w/plastic fibers and a plastic pressure tube

6. Small Imbedded Computer or other digital processor

The system of the present invention may also include a method forselecting optimal LED wavelengths, electrical and electronic methods forjoining components and electronic circuitry coupled with a low costdigital computer (microprocessor) for providing continuous bloodquantity readout. In addition, the fiber sensor could be incorporatedinto the manufacture of the collection container. Also, the shape andconstruction of the whole sensor system could be modified. Likewise, thebasic concept of source, fiber configuration within the blood solution,detector and analysis can be implemented not only by variations in theanalytical processing but also by use of different probe configurations.

For example as shown in FIG. 8, two parallel fibers 302 and 304 withends 302′ and 304′ roughened to produce scattering of light into and outof the fibers 302 and 304. These roughened sections 302′ and 304′ wouldbe in the blood mixture to be measured. Light, indicated by arrows,would both pass through and be scattered from the blood volume. Theparallel fibers 302 and 304, if they are optical waveguides comprised ofcore and cladding, could have cladding 308 and 309, respectively,removed on the facing surfaces to increase light transfer. In addition,the distal ends of the fibers 302 and 304 are provided with mirror films310 and 311 respectively, such as an aluminum coating, to provide areflective surface to prevent light from emanating from the distal endsof the fibers. Those roughened sections 302′ and 304′ can also beachieved by notches incised in the fibers which disrupt lighttransmission from the source and send scattered light into the fluid.Further, the physical configuration of the 302 and 304 fibers can bedifferent, one from the other, to produce a desired wavelengthtransmission profile. Also, the distal end of either fiber could bepolished at a selected angle and coated with highly reflective materialto optimize the amount or distribution of light from the source, orsimilarly optimize the collection fiber.

As shown in FIG. 9, the system may include a plurality of parallelfibers 402, 404, 406, 408, 410 and 412. Each pair of fibers has aconfiguration similar to the pair of fibers shown in FIG. 1. That is,each pair of fibers has angled distal ends to direct light from onefiber to the other. In addition, each pair of fibers is verticallyspaced relative to each other along the probe 420. By obtaining lightreadings over a length of the probe 408, both a depth of the fluid inthe container and average light intensity can be determined. That is,when a fiber pair is not submerged and no light absorption is detected,it can be determined that the level of fluid in the container is belowthat pair of fibers. In addition, for those pairs of fibers that arebelow the level of fluid in the container, an average or comparativehemoglobin concentration can be calculated in the event that thehemoglobin concentration of the fluid mixture is not evenly distributedwithin the container to obtain a more accurate reading.

A simple model illustrates the approach of using a side-emitting fiberwith a parallel receiving fiber. For this it may be noted that theside-emitting fiber can be scribed, etched, cut or otherwise modifiedsuch that the intensity profile along the fiber is constant, that is, itemits a uniform distribution. The receiving fiber likewise can bemodified to intercept the emitted light and transmit some fraction ofthat to a detector to which it is connected. A ray of light incidentnear the top of the receiving fiber will traverse a shorter distancewithin the receiving fiber than one incident near the bottom. For thelimiting case where the receiving fiber conveys the received rays oflight in a lossless manner, the amount of light transmitted and detectedby the receiving detector will be:T=εIo(b/L)

where Io is the incident light emanated by the delivery fiber, ε is theefficiency of capture by the receiving fiber, b is the liquid level, andL is the sensing length of the fiber sensor. This is based on the notionthat light that emanates from the delivery fiber that is underneath thesurface of the liquid may be mostly absorbed by the liquid. Any lightrays traversing the liquid, such as a blood mixture, and which do strikethe receiving fiber will not be efficiently captured and transmittedbecause of the approximate index of refraction matching of the bloodmixture and fiber. Hence only light above the liquid level has areasonable chance of being captured and guided inside the receivingfiber. However, the process of altering the receiving fiber to capturelight that is incident from the side (whether by roughening, cuts, etc.)will also affect how it transmits light up and down its central core.There will be an effective attenuation, α. A first order analysisassumes the common exponential dependence. Consider that for adifferential length segment, dl, of the receiving fiber there will be acorresponding differential value of intensity of the form dI. The totalattenuation of this differential element of light traveling through thefiber will be:

${dI} = {{ɛ\left( \frac{Io}{L} \right)}{\exp\left( {- {al}} \right)}{dl}}$

The total signal that will be received by a detector from all thedifferential elements will be the integral from the location of theliquid surface, b, to the full length of the sensor, L.

$T = {{\int_{0}^{L}{dI}} = {{\frac{ɛ\;{Io}}{aL}{\int_{0}^{L}{e^{- {aI}}{dl}}}} = \frac{ɛ\;{Io}}{{aL}\left( {e^{- {ab}} - e^{- {aL}}} \right)}}}$

To illustrate this further, FIG. 10 is a graph of several hypotheticalvalues of attenuation, α (0, 0.6, 1.2, and 3.0) using the equationabove. The equations are normalized to unit values of initial intensityand sensor length. The value of ε in the equation is simply a constantscale factor in this simplified case. As shown in FIG. 10, the receivedsignal (Total Transmission) based on the fraction of incident is asingle-valued function of the liquid level. Also, as the attenuationincreases, the overall range of the total transmission is reduced. Forexample, for an attenuation of 0, the total transmission ranges from 1.0for an empty canister to 0.0 for a full canister. For an attenuation of3.0, however, the total transmission ranges from about 0.3 for an emptycanister to 0.0 for a full canister. This analysis applies to the designfor which downward scattered light is highly attenuated and is notreflected back. It is also the case that these results can be modifiedand optimized by judiciously altering the side-emitting fiber's lightdistribution to be non-uniform in a way that is advantageous to thepresent invention.

It is further contemplated that two parallel fibers with polished endspointing to a reflecting surface (such as aluminum) could be employed.The gap between fiber ends and the reflective surface would be welldefined and filled with the blood mixture to be measured. In this case,both transported light (from down and back reflectance) and scatteredlight would be measured. It is also contemplated that a singlecontiguous fiber or two fibers which are bent around a tight radius ofcurvature in the blood mixture to be measured could be utilized inaccordance with the principles of the present invention. A notch (for acontiguous fiber) or (for two fibers) a space would be provided forreceiving the blood mixture in the canister. The resulting notch wouldbe triangular in shape so that the optical paths exiting thelight-source fiber would vary in length. Both the curved shape andnon-uniform gap would allow a different, possibly more sensitive,combination of transport and scattering into the collection fiber.

It is further noted that any of the fiber arrangements set forth herein,coupled with the configuration used for depth, can be contained in anintegrated instrumented canister. The canister would have connections atthe top for both the optical and pressure measurements, in addition tothe usual connections for the vacuum source, if needed, and bloodentrance.

In a further exemplary aspect, the processor of the system can beconfigured to receive one or more user inputs, with each inputcorresponding to at least one of the following variables: EstimatedBlood Loss (EBL) of the subject; Volume of the fluid sample; hemoglobinconcentration of the blood of the subject; Estimated Blood Volume (EBV)of the subject; and volume of N fluid administered to the subject.

In a further exemplary aspect, a blood measurement system comprises theblood measurement device of any one of the previously described aspectsand a suction canister, the suction canister having an outer wall havingan internal surface and an external surface, the internal surface of theouter wall defining an interior space configured to receive the probe.

In another exemplary aspect, the probe is integrally formed with thesuction canister.

In another exemplary aspect, the blood measurement system furthercomprises a drip counter configured for communication with anintravenous (N) fluid delivery element, the drip counter is configuredto produce a volume signal indicative of the volume of IV fluiddispensed from the N fluid delivery element and a delivery rate signalindicative of the rate at which IV fluid is dispensed from the IV fluiddelivery element, and the drip counter is positioned in operativecommunication with the processor such that the processor is configuredto receive the volume signal and the delivery rate signal.

In another exemplary aspect, the processor is configured to receive atleast one user input, and each user input is indicative of one of: avolume of one or more intravenous fluids dispensed from a fluid deliveryelement; and a rate at which the one or more IV fluids is dispensed fromthe IV fluid delivery element.

In an additional exemplary aspect, a method of measuring the amount ofblood of a subject within a fluid sample comprises operativelypositioning a blood measurement device of any of the preceding aspectsrelative to a fluid sample; and using the blood measurement device todetermine the concentration of hemoglobin within the fluid sample.

In another exemplary aspect, the method further comprises administeringone or more reagents to the fluid sample, wherein the one or morereagents are configured to convert hemoglobin within the fluid sampleinto one of methemoglobin and sulphemoglobin.

In another exemplary aspect, the method further comprises delivering ananticoagulant to the fluid sample.

In another exemplary aspect, the anti-coagulant is heparin.

Although several embodiments of the invention have been disclosed in theforegoing specification, it is understood by those skilled in the artthat many modifications and other embodiments of the invention will cometo mind to which the invention pertains, having the benefit of theteaching presented in the foregoing description and associated drawings.It is thus understood that the invention is not limited to the specificembodiments disclosed hereinabove, and that many modifications and otherembodiments are intended to be included within the scope of the appendedclaims. Moreover, although specific terms are employed herein, as wellas in the claims that follow, they are used only in a generic anddescriptive sense, and not for the purposes of limiting the describedinvention, nor the claims, which follow.

In the foregoing specification, the present invention has been describedwith reference to specific exemplary embodiments. Various modificationsand changes may be made, however, without departing from the spirit andscope of the present invention as set forth in the claims. Thespecification and figures are illustrative, not restrictive, andmodifications are intended to be included within the scope of thepresent invention. Accordingly, the scope of the present inventionshould be determined by the claims and their legal equivalents ratherthan by merely the examples described.

For example, the steps recited in any method or process claims may beexecuted in any order and are not limited to the specific orderpresented in the claims. Additionally, the components and/or elementsrecited in any apparatus claims may be assembled or otherwiseoperationally configured in a variety of permutations and areaccordingly not limited to the specific configuration recited in theclaims.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to particular embodiments. Any benefit,advantage, solution to problem, or any element that may cause anyparticular benefit, advantage, or solution to occur or to become morepronounced are not to be construed as critical, required, or essentialfeatures or components of any or all the claims.

The terms “comprise”, “comprises”, “comprising”, “having”, “including”,“includes” or any variations of such terms, are intended to reference anon-exclusive inclusion, such that a process, method, article,composition or apparatus that comprises a list of elements does notinclude only those elements recited, but may also include other elementsnot expressly listed or inherent to such process, method, article,composition or apparatus. Other combinations and/or modifications of theabove-described structures, arrangements, applications, proportions,elements, materials, or components used in the practice of the presentinvention, in addition to those not specifically recited, may be variedor otherwise particularly adapted to specific environments,manufacturing specifications, design parameters, or other operatingrequirements without departing from the general principles of the same.

What is claimed is:
 1. A blood loss measurement device for determiningthe amount of blood of a subject within a fluid sample, the fluid samplehaving a volume, the blood measurement device comprising: a suctioncontainer configured for collecting blood lost from a patient during asurgical procedure; a lid coupled to a top of the container; a supportstructure coupled to and vertically held by the lid, the supportstructure vertically extending within the container from the lid toproximate a bottom of the container; a broad spectrum light sourceconfigured to generate light at a plurality of wavelengths; at least onelight sensor configured to detect a first amount of light from the lightsource at the first wavelength from the plurality of wavelengths and asecond wavelength from the plurality of wavelengths that is differentthan the first wavelength; a plurality of optical fibers comprising: afirst optical fiber having a long axis and coupled to the supportstructure so that the long axis of the first optical fiber extendslinearly and vertically within the container, the first optical fiberhaving a first receiving end coupled to the light source and atransmitting end portion opposite the first receiving end disposed inthe suction container with a second end of the first optical fiberpositioned proximate the bottom of the container; and a second opticalfiber having a long axis and coupled to the support structure so thatthe long axis of the second optical fiber extends linearly andvertically within the container parallel to and proximately spaced fromthe first optical fiber so as to allow fluid within the container to bedisposed between the first and second optical fibers along theirrespective lengths, the second optical fiber having a first receivingportion disposed within the suction container with a first end of thesecond optical fiber positioned proximate the bottom of the container,the first receiving portion of the second optical fiber positionedproximate the second transmitting portion of the first optical fiber sothat light emanating from the second transmitting portion of the firstoptical fiber can be at least partially received by the first receivingportion of the second optical fiber, the second optical fiber having asecond transmitting end coupled to the at least one light sensor, theamount of light received by the second optical fiber being detected bythe at least one light sensor to detect an amount of light received bythe second optical fiber from the first optical fiber at the first andsecond wavelengths; and a processor operatively coupled to the at leastone light sensor, the processor configured to receive at least onesignal from the at least one light sensor, the at least one signal beingdependent upon an amount of absorption of light by blood in thecontainer disposed between the transmitting portion of the first opticalfiber and the receiving end of the second optical fiber, the processorconfigured to determine a concentration of hemoglobin in the containerdepending on the at least one signal.
 2. The blood measuring device ofclaim 1, further comprising a volume detection device.
 3. The bloodmeasuring device of claim 2, wherein the volume detection devicecomprises a pressure sensor.
 4. The blood measuring device of claim 3,where the volume detection device comprises a tube having a first endpositioned proximate a bottom surface of the container and a second endcoupled to the pressure sensor, the pressure sensor generating apressure signal and being operatively coupled to the processor, whereinthe processor determines a volume of fluid within the container based onthe pressure signal.
 5. The blood measuring device of claim 2, where thevolume detection device comprises a separate or related signal analysisof selected wavelength bands of light arising from the source, whereinthe specified bands are affected by fluid depth so as to indicate thelocation of the interface of fluid and air.
 6. The blood measuringdevice of claim 1, wherein the plurality of optical fibers comprise aplurality of pairs of first and second optical fibers, the first opticalfiber of each pair having a transmitting end portion proximate to areceiving end portion of the respective second optical fiber, each pairof the first and second optical fibers positioned at a different depthwithin the container to provide a plurality of signals from the at leastone light sensor, each of the plurality of signals corresponding to anamount of absorption of light between one of the plurality of pairs offirst and second optical fibers.
 7. The blood measuring device of claim1, wherein the transmitting end portion of the first optical fiberdefines a first angled end surface of about 45 degrees and the firstreceiving portion of the second optical fiber defines a second angledend surface of about 45 degrees, wherein the first and second angled endsurfaces are substantially horizontally aligned and angled from theirrespective distal ends away from each other so that light transmittedthrough the first optical fiber will reflect off of the first angled endsurface and be directed toward the second angled end surface and bereflected off of the second angled end surface up through the secondoptical fiber.
 8. The blood measuring device of claim 1, wherein a firstlongitudinal portion of the transmitting end of the first optical fiberextends from the second end of the first optical fiber to proximate thelid and faces the second optical fiber and is configured to transmitlight there through toward the second optical fiber and wherein a secondlongitudinal portion of the second optical fiber extends from the firstend of the second optical fiber to proximate the lid and faces the firstlongitudinal portion and is configured to receive the light along itslength from the first optical fiber.
 9. The blood measurement device ofclaim 1, wherein the first wavelength ranges from about 500 nm to about600 nm, and wherein the second wavelength ranges from about 850 nm toabout 900 nm.
 10. The blood loss measurement device of claim 1, whereinthe first wavelength is about 525 nm, and wherein the second wavelengthis about 870 nm.
 11. The blood loss measuring device of claim 1, whereinthe support structure further defines a first longitudinally extendingchannel for housing the first optical fiber and a second longitudinallyextending channel for housing the second optical fiber to maintain aproximate position of the first and second optical fibers.
 12. The bloodmeasurement device of claim 1, wherein the light source comprises aplurality of light emitting diodes (LEDs), wherein at least one LED ofthe plurality of LEDs is configured to emit light at the firstwavelength, and wherein at least one LED of the plurality of LEDs isconfigured to emit light at the second wavelength.
 13. The bloodmeasurement device of claim 12, further comprising a plurality of pairsof opposed optical fibers, each pair of optical fibers comprising afirst optical fiber operatively coupled to a corresponding LED of theplurality of LEDs and a second optical fiber operatively coupled to acorresponding light sensor of the plurality light sensor, wherein theplurality of opposed pairs of optical fibers are positioned within thecontainer so as to be submerged within the fluid sample, and wherein inthe operative position, the plurality of light sensor and the pluralityof LEDs are not in fluid communication with the fluid sample.
 14. Theblood measurement device of claim 1, wherein a distance between thetransmitting portion of the first optical fiber and the receivingportion of the second optical fiber ranges from about 0.05 mm to about0.2 mm.
 15. The blood measuring device of claim 1, wherein theconcentration of hemoglobin and the volume in the container in thecontainer is used to determine a resulting blood loss measurement andwherein the resulting blood loss measurement is used to monitor bloodinfusion during the surgical procedure where blood infusion is beingutilized to limit excess or insufficient blood infusion to ameliorate apatient's condition during the procedure.
 16. The blood measuring deviceof claim 15, wherein the resulting blood loss measurement is used tocalculate infusion volumes of crystalloid or colloid solutions toreplace blood loss during surgical procedures, to limit excess orinsufficient crystalloid/colloid infusions, which can be harmful to thepatient.
 17. A blood loss measurement device for determining the amountof blood of a subject within a fluid sample, the fluid sample having avolume, the blood measurement device comprising: a container configuredto receive a volume of fluid including blood from a patient during amedical procedure; a lid coupled to a top of the container; a supportstructure coupled to and vertically supported by the lid, the supportstructure vertically extending within the container from the lid toproximate a bottom of the container; a plurality of light sources, eachconfigured to generate light at a wavelength different from the otherplurality of light sources; at least one light sensor configured todetect a first amount of light from the plurality of light sources; aplurality of optical fibers comprising: a first optical fiber having afirst receiving end coupled to at least one of the plurality of lightsources and a second transmitting portion extending along a length of afirst side of the first optical fiber, the second transmitting portiondisposed within the container and the first optical fiber verticallyheld within the container from the lid to a distal end of the supportstructure; and a second optical fiber having a first receiving portionextending along a length of a second side of the second optical fiberand facing the first optical fiber, the second side of the secondoptical fiber being coextensive and horizontally aligned with the firstoptical fiber and positioned to receive light from the first side of thesecond transmitting portion of the first optical fiber and a second endcoupled to the at least one light sensor, wherein light emanating fromthe second portion of the first optical fiber is a least partiallyreceived by the first receiving portion of the second optical fiber, thefirst amount of light received by the second optical fiber beingdetected by the at least one light sensor to determine the first amountof light received by the second optical fiber from the first opticalfiber; a processor operatively coupled to the at least one light sensor,the processor configured to receive a signal from the at least one lightsensor, the signal being dependent upon an amount of absorption of lightby blood in the container disposed between the second transmittingportion of the first optical fiber and the first receiving portion ofthe second optical fiber and the corresponding first amount of lightreceived by the second optical fiber, the processor determining aconcentration of blood in the container depending on the signal.
 18. Theblood measuring device of claim 17, further comprising a volumedetection device.
 19. The blood measuring device of claim 18, where thevolume detection device comprises a tube having a first end positionedproximate a bottom surface of the container and a second end coupled toa pressure sensor, the pressure sensor generating a pressure signal andbeing operatively coupled to the processor, wherein the processordetermines a volume of fluid within the container based on the pressuresignal.
 20. The blood measuring device of claim 17, wherein theplurality of optical fibers comprise a plurality of pairs of first andsecond optical fibers, each pair of first and second optical fiberspositioned at a different depth within the container to provide aplurality of signals from the at least one light sensor, each of theplurality of signals corresponding to a detected amount of absorption oflight from one of the plurality of pairs of first and second opticalfibers.
 21. The blood measuring device of claim 17, wherein atransmitting end of the first optical fiber defines a first angled endsurface of about 45 degrees and a receiving end of the second opticalfiber defines a second angled end surface of about 45 degrees, whereinthe first and second angled end surfaces are substantially horizontallyaligned and angled from their respective distal ends away from eachother so that light transmitted through the first optical fiber willreflect off of the first angled end surface and be directed toward thesecond angled end surface and be reflected off of the second angled endsurface up through the second optical fiber.
 22. The blood measuringdevice of claim 17, wherein a first longitudinal portion of thetransmitting portion of the first optical fiber extends from the secondend of the first optical fiber to proximate the lid and faces the secondoptical fiber and is configured to transmit light there through towardthe second optical fiber and wherein a second longitudinal portion ofthe second optical fiber extends from the first end of the secondoptical fiber to proximate the lid and faces the first longitudinalportion and is configured to receive the light along its length from thefirst optical fiber.
 23. The blood measurement device of claim 17,wherein the plurality of light sources comprise first and second lightsources, the first light source configured to generate light at a firstwavelength ranging from about 500 nm to about 600 nm, and wherein thesecond light source configured to generate light at a second wavelengthranging from about 850 nm to about 900 nm.
 24. The blood lossmeasurement device of claim 23, wherein the first wavelength is about525 nm, and wherein the second wavelength is about 870 nm.
 25. The bloodloss measuring device of claim 17, further comprising a housing definingat least one longitudinally extending channel for housing the first andsecond optical fibers and maintaining the proximate position of thesecond end of the first optical fiber relative to the first end of thefirst optical fiber.
 26. The blood measurement device of claim 17,wherein the plurality of light sources comprises a plurality of lightemitting diodes (LEDs).
 27. The blood measurement device of claim 26,further comprising a plurality of pairs of opposed optical fibers, eachpair of optical fibers comprising a first optical fiber operativelycoupled to a corresponding LED of the plurality of LEDs and a secondoptical fiber operatively coupled to a corresponding light sensor of theplurality light sensors, wherein the plurality of opposed pairs ofoptical fibers are configured for selective insertion within the fluidsample.
 28. The blood measurement device of claim 17, wherein a distancebetween the transmitting end of the first optical fiber and thereceiving end of the second optical fiber ranges from about 0.05 mm toabout 0.2 mm.
 29. The blood measuring device of claim 17, furthercomprising a concentration of hemoglobin and a volume of the fluid inthe container used by the processor to determine a resulting blood lossmeasurement and wherein the resulting blood loss measurement is used tomonitor blood infusion during a surgical procedure where blood infusionis being deployed to limit excess or insufficient blood infusion toameliorate a patient's condition during a procedure.
 30. The bloodmeasuring device of claim 29, wherein the resulting blood lossmeasurement is used to calculate infusion volumes of crystalloid orcolloid solutions to replace blood loss during surgical procedures, tolimit excess nor insufficient crystalloid/colloid infusions, which canbe harmful to the patient.
 31. The blood measuring device of claim 17,wherein the second transmitting portion of the first optical fiber andthe first receiving portion of the second optical fiber are eachcomprised of a corresponding plurality of notches to direct light fromthe first optical fiber to the second optical fiber along its lengthdisposed within the container.